3D Tiles Picking Dev

<!--
  示例：拾取调试：屏幕坐标与地表位置
  说明：鼠标移动时在右上角显示屏幕坐标、拾取对象类型与地表经纬度
  核心逻辑：MOUSE_MOVE 事件 → scene.pick 判断类型 → pickEllipsoid 求经纬度 → 写入 HUD
  依赖：CesiumJS 1.121 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>拾取调试：屏幕坐标与地表位置</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Widgets/widgets.css">
<style>
  html,body{height:100%;margin:0}
  body{background:#0e1116;color:#e6e8ec;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  #c{height:100%}
  .tip{position:absolute;left:12px;top:12px;z-index:5;
       background:rgba(23,28,35,.9);border:1px solid #2a313b;border-radius:6px;
       padding:8px 12px;font-size:12px;color:#a2a9b6;max-width:320px;line-height:1.6}
  .cesium-viewer-bottom .cesium-widget-credits,.cesium-viewer-animationContainer,
  .cesium-viewer-timelineContainer{display:none!important}
  .hud{position:absolute;right:12px;top:12px;z-index:6;background:rgba(23,28,35,.92);
       border:1px solid #2a313b;border-radius:6px;padding:8px 12px;font-size:12px;
       color:#a2a9b6;line-height:1.9;font-family:ui-monospace,Consolas,monospace}
</style>
</head>
<body>
<div id="c"></div>
<div class="tip">鼠标在建筑上移动显示 Entity，在空处显示「空」。地表经纬度始终有值。</div>
<div id="hud" class="hud">移动鼠标查看拾取结果</div>
<script src="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Cesium.js"></script>
<script>
(function () {
  'use strict';

  var viewer = new Cesium.Viewer('c', {
    baseLayer: false,
    baseLayerPicker: false, geocoder: false, homeButton: false,
    sceneModePicker: false, navigationHelpButton: false,
    animation: false, timeline: false, fullscreenButton: false,
    infoBox: false, selectionIndicator: false
  });

  var scene = viewer.scene;
  scene.globe.baseColor = Cesium.Color.fromCssColorString('#1c2733');
  scene.backgroundColor = Cesium.Color.fromCssColorString('#0e1116');
  scene.skyBox.show = false;
  scene.sun.show = false;
  scene.moon.show = false;
  if (scene.skyAtmosphere) scene.skyAtmosphere.show = false;

  var seed = 88;
  function rnd() { seed = (seed * 9301 + 49297) % 233280; return seed / 233280; }

  for (var i = 0; i < 12; i++) {
    var h = 16 + rnd() * 34;
    viewer.entities.add({
      position: Cesium.Cartesian3.fromDegrees(116.3866 + (i % 4) * 0.0028,
                                              39.9038 + Math.floor(i / 4) * 0.0024, h / 2),
      box: {
        dimensions: new Cesium.Cartesian3(24, 22, h),
        material: Cesium.Color.fromCssColorString('#4a83d6').withAlpha(0.9),
        outline: true,
        outlineColor: Cesium.Color.WHITE.withAlpha(0.3)
      }
    });
  }

  var hud = document.getElementById('hud');
  var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);

  handler.setInputAction(function (move) {
    var sp = move.endPosition;
    var picked = scene.pick(sp);
    var type = '空';
    if (picked) {
      if (picked.id) type = 'Entity';
      else if (picked.primitive) type = picked.primitive.constructor.name;
      else type = '其他';
    }
    var cart = viewer.camera.pickEllipsoid(sp, scene.globe.ellipsoid);
    var geo = '—';
    if (cart) {
      var c = Cesium.Cartographic.fromCartesian(cart);
      geo = Cesium.Math.toDegrees(c.longitude).toFixed(5) + ', ' +
            Cesium.Math.toDegrees(c.latitude).toFixed(5);
    }
    hud.innerHTML = '屏幕：' + Math.round(sp.x) + ', ' + Math.round(sp.y) +
                    '<br>拾取：' + type +
                    '<br>地表：' + geo;
  }, Cesium.ScreenSpaceEventType.MOUSE_MOVE);

  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3912, 39.8998, 640),
    orientation: { heading: Cesium.Math.toRadians(10), pitch: Cesium.Math.toRadians(-26), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>